1. Field of the Invention
The present invention relates to a system for detecting airflow in a vehicle paint booth.
2. Background Art
Paint booths are used to paint automotive vehicle bodies. A paint booth is divided into multiple zones that may be separated by partition walls. Different operations are performed in each zone. For example, a first zone can be used to remove contaminants from the vehicle body, a second zone can be used to apply a base color or metallic paint flakes, a third zone can be used to apply a clear coat finish, and a fourth zone can be used to xe2x80x9cflash offxe2x80x9d undesired paint solvents. These operations may be conducted by technicians or by robots.
Excess paint mist and airborne particles tend to accumulate within each zone due to the coating processes. These mists and airborne particulates are removed from each zone by passing air through a perforated ceiling and down through the floor of the paint booth. Problems can occur if adjacent zones have different air pressures. Specifically, if one zone has higher air pressure than an adjacent zone, then undesirable cross flow is produced where air moves from the high pressure zone into the adjacent low pressure zone. This cross flow can carry dirt and contaminants into a neighboring zone and contaminate the vehicle body. In addition, cross flow can misdirect the spray of paint and cause uneven painting. Cross flow can also carry different colored paint mists between zones and degrade the quality of the paint finish.
Flow velocity sensors are often mounted in each paint booth zone to detect the velocity of air passing between adjacent zones. In a paint booth with partitions it can be difficult to position a flow velocity sensor to reliably detect cross flow between adjacent zones because the sensitivity of the flow velocity sensor may depend on the direction of airflow. In a paint booth without partitions it is desirable to mount flow velocity sensors between the zones and near the ceiling to reduce the risk of damage, avoid interference with painting operations, and reduce the likelihood of paint contamination on a sensor. Unfortunately, sensors located near the ceiling of a non-partitioned paint booth do not reliably detect cross flow because of air turbulence near ceiling beams and other paint booth structures.
Before the Applicant""s invention there was a need for a system to accurately detect airflow between adjacent zones of partitioned and non-partitioned vehicle paint booths. Problems associated with the prior art as noted above and other problems are addressed by the Applicant""s invention as summarized below.
According to one aspect of the present invention, an airflow detection system and vehicle paint booth are provided. The vehicle paint booth has a partition that separates a first zone from a second zone. The partition includes an aperture that permits air to flow between the first zone and the second zone. A flow velocity sensor is located in the first zone near the aperture and measures the airflow passing through the aperture. An air deflector is disposed on the partition in the first zone near the aperture. The air deflector has at least one air deflection surface spaced from the flow velocity sensor. The air deflection surface directs the airflow passing through the aperture toward the flow velocity sensor to improve the reliability of the system. The flow velocity sensor may be located below the air deflection surface of the air deflector. An adjustable support arm may be used to position the flow velocity sensor or anemometer relative to the air deflector.
According to another aspect of the invention, an airflow detection system for a vehicle paint booth without partitions may be provided. The vehicle paint booth has a first zone and a second zone adjacent to the first zone. A flow velocity sensor is disposed between the first zone and the second zone and measures the airflow between the zones. An air deflector having at least one air deflection surface is disposed near the flow velocity sensor. The air deflection surface reduces turbulence in the airflow near the flow velocity sensor to improve system reliability. A first air deflection surface may be located in the first zone and a second air deflection surface may be located in the second zone. The air deflector may be attached to a beam of the vehicle paint booth to influence the air turbulence beneath the beam.
According to other aspects of the invention, the air deflector may have a vertical axis longer or shorter than a horizontal axis. In addition, the air deflector may have a triangular cross-section. The air deflection surface may be concave, convex, dimpled, substantially planar, or combine various combinations of these surfaces.